What gets silver Cad rather than yellow?

[mdsalemi]

Remember guys, zinc, or zinc with a phosphate wash (gold zinc) are sacrificial coatings. The moment they hit the atmosphere they begin to degrade. First, the gold color dissipates and this protective passivation disappears, then the underlying zinc eventually oxidizes and sloughs away leaving you with raw cast iron. The raw cast iron isn't in any danger of "rusting away" like sheet metal, so it becomes more of a cosmetic thing. I've never heard anyone say, "Oh, my cast iron brake calipers rotted away!" If that were to ever happen I'd think there wouldn't be much automobile left...

Remember, the standards of zinc or cadmium plating is done with a salt spray test, and the results are measured in hours, not decades...

The caliper rebuilders (of which I pointed to a few previously in the USA) will do pretty much whatever finish you want on the rebuilt calipers. You can get a plating as noted--still sacrificial and not long for this earth--or paint, baked on or rattle can, or powder coat. And of course, if you paint or powder coat you can get it to look like plating if you so choose.

[wwheeler]

When I restored the underside of my W111, I chose the yellow CAD/zinc look for the calipers. I had seen it somewhere and looked original, so I went for it. Because my calipers were new, I decided to use a high temp caliper paint to get that look. It was a concoction of various colors to get close. Besides, I was not sure what the plating process would do to the critical bore finish in the caliper. BTW, the red inspection dots were on the lock plate and bolts before I took it apart. And also for reference, the calipers as from ATE were a clear zinc finish that has a slight blue tint from the chromate.

[Shvegel]

Wallace, Thanks so much for posting that picture.  I was sure my axle had red dots on the housing where the caliper bolts were but neglected to take a picture of them.  i have been looking for a picture online but had not found one yet.  That was what I needed to finish my rear axle.  Done!

[johnk]

So I took Mike's advice and bought a $40 tumbler at harbor freight along with coarse walnut shells and a $13 package of polishing compounds. The results are amazing and everything comes out looking like new silver cad and it only takes about 5 minutes every two days to screen out the clean parts and put in a dirty batch. Very little effort for the results. Because I bought the small tumbler I cant put in parts greater than 4 inches or so. Of the four types of polishing compound that come in the package the "pre=polish" seems to work the best is making the parts look new before they go in for plating.

[wwheeler]

Pat, No problem on the pic and glad it helped. I made several notations of the paint dabs when I took the rear apart and also took pics of the front end parts for that future project. These cars are loaded with inspection dabs and much more so than my '60 Ponton coupe. Not all of the dabs survive time and so you find some on yours and compare to someone else's. 280SEGUY used to have a picture site and had many inspection dabs from his beautifully maintained 280SE sedan. You might PM him to see if that still exists. BTW, how did you finish your caliper to get the yellow CAD look?

I will look into the tumbler and thanks for reviewing that. 

[Shvegel]

Wallace, I started rebuilding my old calipers. I cleaned them up and had them plated then decided to just buy 4 new ones...ouch!   They came silver zinc and were already mottled in spots so I decided to dust them with a "concoction" of 2 colors of paint removing 2 bolts at a time then overcoated it with Nyalic which is a low gloss clear that they use on Airstream trailers.  It is pretty bizare stuff that I use on all my aluminum parts.  A light coat is undetectable but on the calipers I went a little heavy.  If it doesn't burn right off hopefully they will stay gold for more than a minute.

This detail stuff is a drug.  I enjoy it but right after I took that picture I made new brake lines because these had an extra bend at the caliper that wasn't supposed to be there.

Is that an original Phoenix tire on on your SE?

[wwheeler]

Yes, I am a detail junkie as well and appreciate your struggles for perfection! No, those are Coker's tires. If had to get new tires, I would go with the Diamond Back WW w/ Vredestein. I have those with the wide WW on my Ponton coupe and the white stays white. I struggle with the Phoenix WW as they yellow and stain quickly. BTW, I clear most of my parts with either Hi temp engine clear (w/ ceramic) or a version of Nylac.   

Fun, fun, fun.

[mdsalemi]

So I took Mike's advice and bought a $40 tumbler...results are amazing and everything comes out looking like new...very little effort for the results.

I would not steer you wrong. I've had my vibratory tumbler for years. When I owned a car wash I made change in tokens, not cash--and often when the tokens came back or if they sat in a wet coin box for a while, they came to be pretty nasty. So every few weeks, I'd take the load of them, dump them into the tumbler and let them vibrate away for a few days. Voila--new looking tokens. I've since used it for a number of things automotive related on the Pagoda...

[wwheeler]

I would not steer you wrong. I've had my vibratory tumbler for years. When I owned a car wash I made change in tokens, not cash--and often when the tokens came back or if they sat in a wet coin box for a while, they came to be pretty nasty. So every few weeks, I'd take the load of them, dump them into the tumbler and let them vibrate away for a few days. Voila--new looking tokens. I've since used it for a number of things automotive related on the Pagoda...

I just bought mine from HF and lets see how it does. I bought both plastic bits and ceramic. I agree, for small nuts, bolts and especially flat washers, this could be a real time saver. Flat washers are a pain to abrasive blast. You have to get the entire surface spotless or else it will show up as a blight when plated.

[dirkbalter]

I have a tumbler too and can confirm that it takes a rather long time to clean up parts. I had my hood hinges in there for a week until they were “clean”. That’s why I am surprised to see that one would attempt to clean or blast off the shelf standard parts? For example, 6mm flat washers are anywhere from $2 to $5 depending on the finish / material for a bag of 100?   

[wwheeler]

True. But some washers are not common sizes and one cannot find a yellow CAD plated washer in the hardware store. Zinc yes, but not CAD. I typically clear most of my plated hardware after installation. The clear significantly prolongs the life of the plated finish but is only effective on freshly plated parts. The plating on hardware bolts is an unknown age and has already probably started to bloom and degrade. Yes, I am a detail junkie as I said earlier.

But, I do not reuse split lock washers. I tried plating some in the past and they broke during installation due to hydrogen embrittlement. I am not going to go to the expense of treating those. And, those are typically all standard sizes.   

[Shvegel]

For lock washers (Both split and "wavy") I just buy new ones from Belmetric.